The United States (US) has had a pretty violent history and is very well known for its enslavement of colored folk. However in 1863, President Abraham Lincoln issued the Emancipation Proclamation which technically ended slavery, however slavery within the United States wasn’t completely abolished until December 6th, 1865.
Despite that you could no longer legally own slaves within the US after 1865, slavery still exists today and racial tensions are still present today. The US is a dramatically better than pretty much most of the world in human rights and racial acceptance. There are even attempts at advertisements to teach Americans how to recognize slaves in the 21st century. However the rest of the world is not up to par with the US and similar nations such as Canada. In a lot of more underdeveloped and developing countries, slaves are not hidden at all. As can be seen from the images below, Libyans are still importing and using slaves at full force. It can be seen that these people being used as slaves are being treated in conditions far from humane as you can see by their blood stained shirts, scars and malnourished bodies in the images below. (Viewer discretion is advised)